The present invention generally relates to a document feeding arrangement, and more particularly, to an automatic original document feeder for automatically feeding original documents to be copied, to an image exposing position successively.
Commonly, an electrophotographic copying machine is provided with a transparent original document platform for subjecting an image of an original document to be copied, to exposure and scanning, and so arranged that, by exposing for scanning, the original document placed at a predetermined or specified position on this original document platform through an optical means, the image of the original document is projected onto a photosensitive member serving as a recording medium, whereby an electrostatic latent image of an original document is formed on the photosensitive member.
Therefore, in the case where many original documents must be dealt with for copying, there has been required an extremely troublesome manual procedure for placing the original document to be copied on the original document platform one sheet by one sheet, thus increasing the time required for performing the work. Accordingly, in order, to eliminate this troublesome manual operation and for simplification of the copying operation, an arrangement referred to as an automatic original document feeder has been developed so as to automatically transport the original document to an exposing position.
The automatic original document feeder as referred to above is, for example, so arranged as to feed original documents stacked at a predetermined position, one sheet at a time, for automatic transport thereof into the exposing position, and also to transport the original document onto a discharge tray different in position from the stacked position after completion of the exposure. Here, in the case where the original document is of a duplex or both sided original document, it is necessary to feed the original document to the exposing position at both faces for the duplex copying or one side face copying thereof. For this purpose, the automatic original document feeder is provided with an inverting transport section for turning over or inversion between the front face and reverse face of the original document.
As described above, through turning over between the front and reverse surfaces of the original document via the inverting transport section during transport of the duplex original document to the exposing position, opposite surfaces of the original document may be fed into the exposure position for exposure and scanning on both surfaces.
However, in the conventional arrangement, control is provided such that the transported original document is fed to the inverting transport section as it is so as to be transported to the exposing and scanning position through the inverting transport section, and thus, the transport passage for the original document becomes very long, resulting in a slantwise or diagonal feeding of the original document in some cases. If the original document is transported to the inverting transport section as it is fed slantwise as described above, damages to the original document or jamming thereof may take place.